Advanced camera tools - creating a specific camera

Hi All
i am using advanced camera tools to design a film set with printed back drops - i am using ACT to work out shots with the DOP and work out exactly how big the backdrops need to be and the positioning of the art works etc - works like a charm but i have my concerns over accuracy as it is so critical to get the back drop art works and sizes spot on . - i have been using the Alexa Arriraw camera type which is 16:9 - the real world camera we are using on the shoot is a > Alexa 35 4.6k 16:9 (4608x 2592) how can i accurately simulate that camera and a 25mm lens ? i have no experience with CSV files - was hoping for a quicker fix ! thanks !

If you’re getting ACT to work for you, congratulations! I’ve struggled with the interface and work flow myself. I don’t know how to make custom cameras. I’m a lifelong still photographer and only a beginner at video/cinematography as yet, so I’m not as familiar with those sensor sizes and optics.

I put some effort into checking SketchUp’s angle of view and focal length etc and found:

  1. If you’re NOT using ACT (just every day SketchUp), there’s a bug where SU reports wrong numbers for focal length, so don’t rely on that.
  2. ACT seems to not have this bug and reports them correctly, so as long as you’re using that, it should work.
  3. There is also a Safe Frames plugin, and focal length seems to report correctly when using that.

The thing you can rely on with every day SU use is the vertical angle of view. No matter how you resize your window (which affects aspect ratio), SU holds that and the horizontal angle of view floats.

A good online resource I found for real world cameras it this one:

Kind of an online calculator one lens at a time, but I’ve used the formulas to build an Excel worksheet. That would be the pathway to generating a CSV file. What data is it that ACT needs in a CSV?

I double checked what I was figuring out by making my own frustrum as a SketchUp object. I made it so you can tilt, pan and zoom with it, but not truck. What I made was based on 35mm full frame still camera sensor, so it wouldn’t apply to your camera. It would have to be rebuilt to do that.

thanks ! checking it out

my question now is how do i set a specific camera sensor size - width and height ? ACT only allows you to set width and i assume it calculates hight from the aspect ratio ?

That’s correct. No need to set the height. The CSV file is easy enough to edit and add a camera to if you need it. Or just pick a different camera with the same aspect ratio.

Maybe you don’t understand Aspect Ratio. According to your first post the sensor size is 4608 x 2592. The Aspect Ratio is 16:9. The aspect ratio for your camera could be written as 4608:2592 but aspect ratio is normally given as a simplified fraction. 4608/2592 equals 1.7778. 16/9 also equals 1.7778. With the Advanced Camera tools you can choose the existing Alexa Arriraw camera

The Lens focal length is then set in Camera>Field of View. Find the horizontal angle of coverage for the lens on that camera and use that to set Field of View.

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thanks for taking the time with this thread - i am trying to replicate this camera and lens : Alex 35 4.6k 16:9 (4608x2592) (Recording Format Sensor Size 27.99x15.75) and a Leica Summilux or Generic 29mm. this is beyond my normal use of ACT and understanding of photography - i usially use Arriraw or monitoring/EVF for set design - on this project i am needing to design critically sized and positioned backdrops to this specific camera . so as i understand it i would choose the arriraw which has a 16:9 (1,7778) format , set the image width to 27,99 and the focal length to 29mm simple as that ?

That makes sense. I should think that would work.

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How do you get to that dialog? Nothing I can find brings up that dialog box.

Edit: I finally found it. Right click anywhere while looking through the camera. Ugh.

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